Firing mechanism for firearms



G. H. FREED FIRING MECHANISM FOR FIREARMS 2 Sheets-Sheet 1 Filed Oct 24, 1965 INVENTOR. 650/865 7. @550 BY $74M, a My 1967 G. H. FREED 3,337,979

FIRING MECHANISM FOR FIREARMS Filed Oct. 24, 1965 2 Sheets-Sheet P INVENTOR. T 4- 650,965 b. @550 BY A hfzlz Mam United States Patent )fitice 3,33 7,9 79 Patented Aug. 29, 1967.

3,337,979 FIRING MECHANISM FOR FIREARMS George H. Freed, Change Bridge Road, Pine Brook, NJ. 07058 Filed Oct. 24, 1965, Ser. No. 504,931 18 Claims. (Cl. 42-65) ABSTRACT OFITHE DISCLOSURE Adjustable-pull trigger mechanism improvement. Colt revolver having short-throw hammer and adjustable-pull trigger features of U.S. Patents Nos. 3,158,949 and 3,245,- 167; adjustable spring in handle for adjusting rebound lever pressure on trigger (via hand element); and projecting pin on hammer engageable with cam slot in rebound lever during single-action and double-action cocking to relieve rebound lever pressure on trigger.

This application is a continuation-in-part of my copending application Ser. No. 437,074, filed Mar. 4, 1965, now Patent No. 3,245,167, entitled Firing Action Mechanism for Firearms. Reference is also made to my issued Patents Numbers 3,158,948; 3,158,949; and 3,158,950, all of which issued on Dec. 1, 1964.

The present invention relates to further improvements in such firing action mechanisms, particularly with regard to the force which must be employed to pull the trigger when discharging the firearm, the so-called lock time of the mechanism, and the amount of impact of the hammer firing pin on a cartridge which is afforded by the mechanism when triggered.

Although the invention was achieved upon adaption of a Colt model revolver to incorporate its features and will therefore be described in connection with such Colt firearms, it will be understood that the invention in its several aspects may have application in other types of pistols, and in other types of firearms and cartridge firing devices.

My aforementioned Patent 3,245,167 describes a means in Colt model revolvers whereby the amount of force required to pull the trigger of the pistol is subject to adjustment, and may be reduced to but a few ounces as compared with from- 2 to 4 /2 pounds of force as conventionally required. The referred to means includes provision of a spring biased plunger mounted in adjustable fashion on the trigger for contacting a frame member of the pistol during the movement of the trigger in firing the device. In counjunction with the plunger, the preferred arrangement there described includes a modification of the sear element of either the trigger or the hammer of the mechanism, or both of these sear elements, to shorten and/ or angulate the same with respect to each other to an extent which, absent the spring biased plunger, would be regarded as unsafe for the purpose of retaining the required interlock of these sear elements when the trigger has moved to its position in which a so-called singleaction cocking of the pistol has been effectuated. That is, the sear arrangement tends to cooperate with the conventional mainspring bias on the hammer to cause an urging of the trigger, when in its single-action triggering or interlocked position, towards its triggered or fired position over the opposition of the opposite acting return spring pressure on the trigger as is then exerted by the rebound lever which is conventionally incorporated in this type of mechanism. However, at such time the bias pressure of the trigger plunger augments the bias pressure of the rebound lever'at least to the extent necessary to avoid accidental triggering of the mechanism as would otherwise occur. Thus, the extent of adjustment of the trigger plunger bias pressure as may be made to effect a minimum trigger pull to trigger the mechanism is limited to that amount of plunger bias pressure as is required to supplement the urging of the rebound lever so as to avoid override of the interlocking trigger and hammer sears when the trigger is in its single-action triggering position, albeit the trigger pull may be reduced to buta few ounces.

The present invention improves upon both the operation and the safety of this arrangement by providing means for reducing or relieving the bias pressure of the rebound lever on the trigger when the trigger is in such triggering position so as to eliminate the need for such shortening or angulating of the trigger and/or hammer sear elements, yet permit even further adjustment of the trigger plunger bias pressure to an extent where virtually no measurable trigger pull is required to trigger the now safely cocked weapon. The effects can also be produced during a double-action firing of the mechanism at the time when the trigger has virtually achieved its triggering position.

Also depending upon its embodiment, the invention further achieves an increase, and adjustability within the range of increase, in the tension of the mainspring of the mechanism at the time when the weapon is cocked for firing, by either single action or double action movement, this feature being of particular significance where the Weapon includes provision for a short throw hammer movement as described in my aforementioned Patent Number 3,158,949. That is, upon triggering the weapon, the increased tension in the mainspring which acts directly on the hammer affords greater impact of the hammer firing pin on the cartridge which is being fired, thereby assuring an explosion of the cartridge. Although the short throw hammer mechanism of the referred to patent achieves hammer impact force above the minimum requirements in this regard, the means provided by the present invention improves the action of such minimum lock-time mechanisms by guaranteeing that no misfire will occur.

Briefly describing the invention, it should first be understood that the conventional action mechanism in connection with which the invention will be described includes a single mainspring which exerts its bias pressure on both the hammer element and the rebound lever of the mechanism, the latter also normally being in engagement with or acting upon the trigger element for automatically returning the trigger to its prefiring position after the weapon has been fired. As will also be understood, a singleaction firing of the weapon requires that the hammer element be manually cocked against the bias of the mainspring, the hammer concurrently eifecting movement of the trigger towards its triggering position until the singleaction hammer sear achieves interlock with the trigger sear. So-called double-action firing of the weapon merely requires that the trigger be pressed from its normal position towards its firing position, the trigger sear engage ing the double-action hammer sear and effecting a withdrawal of the hammer during the movement. During either of these movements, the rebound lever continually exerts its bias pressure on the trigger.

For use especially with the mechanism as it includes a spring biased trigger pull adjustment plunger on the trigger in accordance with my referred to Patent No. 3,245,167, the present invention provides a laterally protruding hammer pin, mounted in fixed position at a distance away from the axis of pivotal movement of the hammer, which engages a notch or slot of the rebound lever so as to cam the rebound lever away from its engagement with' the trigger (actually, the hand element which is mounted on the trigger) as the trigger approaches its triggering or firing position. The arrangement may be such that such lifting of the rebound lever occurs only during single-action movement of the mechanism, or it may be arranged so that the same occurs also during double-action movement. Thus, the return spring bias which conventionally is exerted on the trigger at all times during its movement is relieved during the terminal period of trigger movement to its firing position, and it will be noted that the trigger spring biased plunger is at such time exerting slight return spring pressure on the trigger in accordance with its adjustment.

These effects may also be achieved, in accordance with the invention, albeit to a lesser extent, by only providing an additinoal frame mounted spring which exerts its bias pressure on the underside of the rebound lever such that trigger return spring pressure is substantially reduced. As will be seen, the tension in such additional spring may be made subject to adjustment whereby the amount of reduction of trigger return spring pressure may be determined and controlled.

However, the referred to additional spring which acts upon the underside of the rebound lever also effects some compression, and therefore an increase in the tension of the V-shaped mainspring whose lower leaf engages the upperside of the rebound lever. Of course, such increased tension in the mainspring will cause the hammer to strike a cartridge with greater impact when the mechanism is triggered. It therefore becomes apparent that the action of such additional spring affords additional advantage where the mechanism includes means as described in my aforementioned Patent No. 3,158,949 which provide a so-called short throw of the hammer element when the pistol is cocked by single action movement, or by both single-action and double-action movement. That is, the withdrawal or pivotal movement of the hammer element from its fired position towards its cocked position depresses the mainspring such that the mainspring exerts the required tension on the hammer, when it has achieved its cocked position, for hurling it forward upon triggering the device with sufiicient cartridge impact force. Where the distance of such hammer withdrawal is shortened as in a short-throw hammer arrangement of the mechanism, the extent to which the main spring is tensioned for the purpose is lessened. The referred to additional frame mounted spring of the invention, which increases mainspring tension as has been described, restores the loss in mainspring tension as otherwise occurs when the short-throw hammer features are incorporated in the mechanism.

It further becomes apparent that the operation of such a firing action mechanism which includes both the referred to short-throw hammer and adjustable pull trigger features is considerably improved where the mechanism includes both the hammer pin and rebound lever camming slot feature and the referred to additional spring feature.

These and other objects, features and advantages of the present invention will become more fully apparent from the following detailed description thereof, when taken together with the accompanying drawings in which:

FIGURE 1 is a fragmentary side view of a Colt model revolver, having both a short-throw hammer movement in accordance with my Patent No. 3,158,949 and an adjustable pull trigger in accordance with my Patent No. 3,245,167, and further incorporating the present invention;

FIGURE 2 is an enlarged fragmentary showing of the operation of the revolver of FIGURE 1;

FIGURE 3 is a similarly enlarged fragmentary showing of a revolver having all of the features of the revolver of FIGURE 1, but showing a modification of the present invention, the figure being further for the purpose of showing the details of the mechanism when in its prefiring or released position; and

FIGURE 4 is a showing of a double-action movement of the revolver of either FIGURE 1 or FIGURE 3.

Referring first to FIGURE 1, the invention is shown as embodied in a revolver type pistol 20, such as a Colt revolver, which has a frame, generally indicated by reference numeral 21, to which is attached a barrel element 22 and a pivotable cylinder crane 23. A cartridge chamber cylinder 24 is rotatably mounted on a spindle of the crane 23 in conventional manner. It will be understood that the cylinder 24 has a plurality of annularly spaced and axially aligned cartridge receiving chambers formed within the cylinder for receiving a corresponding plurality of cartridges (not shown), each of which may be brought into alignment with the barrel 22 of the gun by rotation of the cylinder, as is well known.

The pistol 20 has a firing action mechanism, generally indicated by reference numeral 26, for firing in sequence the cartridges contained in the cartridge receiving chambers. The firing action mechanism includes a trigger 27 which is pivotally mounted on the frame 21 by a trigger pin 28, a hammer 29 which is pivotally mounted on the frame 21 by a hammer pin 30, a rebound lever 31 which is pivotally mounted at one of its ends 31a on frame 21 by a pin 32, a pistol mainspring 33, and a ratchet pawl or hand element 34 for rotating the cylinder 24 substantially contemporaneously with trigger actuation to index one of the cartridge receiving chambers into firing alignment with the barrel 22. In rotating the cylinder 24, the hand element 34 engages a ratchet element 35 which is attached to the cylinder.

A hammer stirrup 36 is pivotally mounted on the hammer 29 by hammer stirrup pin 37, and it will be understood that the free end of one of the leaf portions 33a of mainspring 33 is in bias pressure engagement with the end 36a of the hammer stirrup in a manner urging hammer 29 toward its released position as shown in FIGURE 1. The other leaf portion 33b of mainspring 33 is in bias. pressure engagement with rebound lever 31 in a manner normally urging the hand element 34 and trigger 27 into their initial, prefiring positions as shown in FIGURE 1. The two leaf portions 33a and 33b merge at the mainspring end 330 which is received in a recess 38 of the frame 21, as shown.

The free end 31b of the pivotable rebound lever 31 is tapered in the illustrated conventional manner and engages a protruding axle housing portion 34a of hand 34 in which a hand axle 39 is attached. The laterally protruding hand axle 39 is received within a trigger slot 49 for both pivotal and rectilinear movement with respect to the trigger 27. The pivotal portion of the movement is that which is conventional in pistols of the type during chamber indexing movement of the hand 34 towards the cylinder 24. However, the rectilinear portion of the hand movement with respect to the trigger is that which is necessary to permit the hand 34 to move toward the cylinder at a rate which is greater than that with which the trigger itself will move in the same direction, this for purposes as fully explained in my Patents Nos. 3,158,948; 3,158,949; and 3,158,950. The trigger 27 also includes a trigger sear portion 41 which, in the preferred embodiment, is adapted in a manner as will be described.

The general arrangement of the firing action mechanism 26 is similar to that of conventional mechanisms in pistols of the type as regards the interacting relationships between the trigger 27 and hammer 29, and it will be understood from FIGURES 2 and 4 that upon pivoting of the trigger 27 in the direction of arrow A, or of the hammer 29 in the direction of arrow B, and depending upon whether the hammer is manually cocked for single action firing (as illustrated in FIGURE 2) or is cocked coincidentally with trigger actuation for double action firing of the pistol (as illustrated in FIGURE 4), the trigger sear portion 41 will engage either the single action hammer sear 52 or the double action hammer sear 53. The double action hammer sear 53 is formed by a surface of a hammer sear strut 54 which is pivotally mounted on hammer 29 as by a strut pin 55. The scar strut 54 has a stop 56 which engages a coacting stop 57 of hammer 29 in response to the bias of a strut spring 58, as shown.

Referring to FIGURES 2 and 3, the firing action mechanism arrangement conventionally includes a cylinder stop element, or bolt 59, which is pivotally mounted for rocking type movement on a bolt pin 60 attached to frame 21. The bolt 59 has an end 61 which is adapted to sequentially engage and disengage each of the peripherally spaced cylinder detents 62 within the cycle of each chamber indexing rotative movement of the cylinder 24. Bolt 59 has an opposite end 63 adapted to engage a laterally projecting lug 64 of rebound lever 31. The rebound lever 31 is biased into engagement at its free end 31b with the hand element 34 (at its housing portion 34a) by urging of mainspring 33 for the purpose of returning the hand element 34 and trigger 27 to their prefiring positions after hammer 29 has been released in firing a cartridge. But it will be seen that the rebound lever 31 will pivot against its bias, in the direction of arrow C, as hand element 34 moves upwardly in engagement with the cylinder ratchet 35. During such upward pivotal movement of the rebound lever 31, the end 63 of bolt 59 will also be urged upwardly by engagement of the laterally projecting rebound lever lug 64 so that its end 61 moves downwardly out of engagement with one of the cylinder detents 62, into which the end 61 has previously been biased by the urging of the bolt spring 65. Upon further movement of rebound lever in the direction of arrow C in response to continued upward movement of the hand element, the bolt end 63 rides off the rebound lever lug 64, thereby permitting the bolt 59 to pivot in opposite direction, responsive to the urging of the bolt spring .65, so that its end 61 may thereupon be biased into seating engagement within the cylinder detent 62 which is next in sequence around the cylinder upon the chamber indexing movement of the cylinder 35 having been completed, as is understood by those having skill in the art.

As is also well understood, upon the trigger and hammer sear elements riding apart in response to additional movement of trigger 27 in the direction of arrow A to fire the pistol, and upon the trigger 27 being released by the finger, the urging of mainspring 33 will cause the rebound lever 31 to pivot in direction opposite to that shown by arrow C. Such pivoting of the rebound lever 31 returns the hand element 34, as well as trigger 27, to their normal, prefiring positions thereby completing the chamber indexing cycle.

Consider the movement of hammer 29, it should be noted that, in the preferred embodiment of the invention,

the fully cocked position of hammer 29, as indicated by the full line showings thereof in FIGURES 2 and 4, is

such as provides a relatively short distance of hammer fall upon its release to strike a cartridge, as compared 'to the distance of hammer fall in a conventional firing action mechanism having generally the same basic mode of operation. Such shortened throw of the hammer 29 is relative to each other, a is Well known to those familiar with the art. For purposes of comparison, the distance of hammer throw in such conventional mechanism is indicated by dotted lines CFC (conventional full cock), the released position of hammer 29 being indicated by dotted lines R. It will be noted that, in either a single-action movement or a double-action movement of the mechanism 26, the throw of the hammer in withdrawing the same from its released position to its fully cocked position in the preferred embodiment is approximately onehalf of that in the basic conventional mechanism, yet is such as to achieve complete and full chamber indexing by the time the hammer 29 has attained its short throw fully cooked position. In addition, it should be noted that the distances of hammer cocking movement during both the single-action movement and the double-action movement are substantially equal.

For an understanding of the means whereby the distance of hammer throw when cooking the mechanism 26 manually in a single-action movement is made substantially equal to that when the mechanism is actuated by a squeezing of the trigger 27 in a double-action movement, reference is made to my aforementioned Patent No. 3,15 8,949. Sufiice it to say here that the extreme end of trigger sear portion 41 is employed for triggering the hammer only during the double-action movement of mechanism 26, and it will therefore be referred to herein as the double-action sear of the trigger 27. Further, the trigger sear portion 41 is notched, as shOWn, at its underside to form a single-action sear 81 of the trigger 27.

Hand element 34 is provided with a laterally protruding portion 83 which provides at a lower edge thereof what will be referred to herein as a hand sear 84. Upon pivoting the trigger 27 in the direction of arrow A, whether such pivoting be caused by finger pressure (double-action movement) or by the pressure of engagement of hammer single action sear 52 with the underside of trigger sear portion 41 (single-action movement), it will be understood that by reason of the tapered juxtapositioning of hand sear 84, an upwardly projecting cam surface 86 of the trigger 27 will exert pressure on hand sear 84 and urge the same in the upward direction relative to trigger 27. Thus, within a relatively short space of pivotal movement of the trigger 27, the hand element 34 will be urged upwardly in engagement with the cylinder ratchet 35 at a relatively rapid rate, the hand axle 39 moving upwardly within trigger slot 40. The cylinder 24 will thus have been rotated fully to the extent necessary to bring a cartridge chamber into alignment with the barrel 22. However, it will be understood that, to cause the trigger and hammer sear elements to ride apart so as to release the hammer from its fully cocked position in either case, a small amount of additional movement of trigger 27 in the direction of arrow A is necessary. Since no further upward movement of hand element 34 is desired during such further movement of the trigger, the upward end of trigger cam surface 86 is provided with a dwell portion on which the lowermost edge of hand sear 84 will ride during such additional trigger movement without causing further upward movement of the hand element.

It will be observed that at all times during the movement as has thus far been described, whether by singleaction or double-action actuation, the rebound lever 31 would normally be in engagement with hand element axle housing portion 34a, under the bias pressure of mainspring 33. Thus, the pressure exerted on trigger 27 which causes its pivotal movement would ordinarily be such as to overcome the bias pressure of mainspring 33 so as to pivot rebound lever 31 against the same, in the direction of arrow C.

In an embodiment as exemplified by FIGURES 1 and 2, the present invention provides a spring 90, which is attached as by a press fit to the frame 21 at its handle portion 21a as shown, for the purpose of exerting upward bias on the underside of the rebound lever 31 to reduce the amount of downward pressure which is exerted by the latter on the trigger 27 via the hand element portions 34a, 83. The amount of bias pressure exerted by the spring 90 may be adjusted by rotational adjustment of the tension adjustment pin 91 which threadedly engages the frame portion 21a as shown. Thus, without more, by adjustment of the pin 91 in or out, the tension of the spring 90 may be increased or decreased, respectively, to respectively reduce or increase the trigger return spring pressure of the mechanism. In this connection, the spring 90 may be positioned such that maximum withdrawal of the pin 91 virtually relieves all of the pressure which the spring exerts on the underside of the rebound lever 31, thereby providing the maximum return spring pressure of the mechanism. However, the -pin 91 should never be moved inwardly a distance sufiicient to cause the bias pressure of the spring '7 90 to be such as to lift the rebound lever 31 out of its engagement with the hand element portion 34a when the trigger 27 is in its released position as shown in FIGURE 1, as would interfere with the full return of the trigger to its normal position after the pistol has been fired.

The spring 90 additionally serves to augment the bias pressure on the upper mainspring leaf 3311 on the hammer stirrup 36, especially when the hammer 29 has been moved in the direction of arrow B towards its fully cocked position as shown in FIGURES 2 and 4. Such increased urging of the mainspring 33 on the hammer stirrup 36 will, of course, increase the amount of impact of the hammer firing pin 29a on a cartridge within the cylinder 24, Thus, in a conventional revolver of the type, the mechanism may be adapted to incorporate a short throw hammer movement without the necessity for substituting a new, stronger mainspring 33 for the purpose of assuring that the mechanism meets cartridge impact requirements.

Rather than being in leaf spring form as is the spring 90, the additional spring provided by the invention may be a coil type spring as shOWn in FIGURE 3. The coil type spring 93 is mounted for freely slidable movement in the direction of its bias on an adjustment pin or shaft 94 which is in threaded engagement with the frame portion 21a as shown. The lower end of the spring 93 abuts against a stop 95 which i secured to the adjustment shaft 94 at an appropriate location depending upon the length and minimum tension to be exerted by the upper end 93a of the spring on the underside of rebound lever 31. The upper end 94a of the adjustment shaft 94 is slidable within a bore 96 of the rebound lever 31. Thus, if the upward pressure to be exerted by the spring 93 is to be increased, the shaft 94 i threaded upwardly so as to shorten the distance between the spring stop '95 and the underside of the rebound lever 31. Conversely, if tension is to be reduced, the shaft 94 is threaded downwardly.

Of course, in both embodiments, a locking screw 97 may be provided to fix the adjusted position of either the pin '91 or the shaft 94.

The invention also provides a laterally projecting pin 98 attached in fixed position on the hammer 29 for engagement with a notch 99 formed in the upper edge of the rebound lever 31, in the manner indicated by a comparison of FIGURES 1 and 3 or either of FIGURES 2 or 4, to fully relieve the return spring pressure exerted by the rebound lever 31 on the trigger 27 at the time when the trigger and hammer elements are in their cocked positions as shown in either of FIGURES 2 or 4. That is, during the terminal portion of either single-action or doubleaction cocking movement of the mechanism, the pivotal movement of the hammer results in arcuate downward movement of the pin 98 into engagement with the cam surface 99a of the notch 99 of the upwardly moving rebound lever 31 to induce faster upward movement thereof so that the forward end 31b of the rebound lever lifts out of engagement with the hand element portion 34a, and it will be understood that at such time the rebound lever 31 ceases to apply return spring pressure on the trigger 27. Therefore, when in its single-action cocked position as shown by FIGURE 2, or as the trigger 27 achieves its triggering position during double-action movement as shown in FIGURE 4, the mechanism may be theoretically triggered with virtually no additional pressure exerted on the trigger 27. However, careful consideration of the operation of the mechanism will reveal that some return spring pressure, acting in the direction opposite to arrow A, must be exerted on the trigger 27 if the hammer and trigger sear elements are to retain their interlocked relation with some firmness, which is especially important when the mechanism is in its single-action cocked position as shown by FIGURE 2.

Careful determination of the location and curvature of the rebound lever camming surface 99a with respect to the location of the pin 98 and the engagement relationship between the rebound lever forward end 31b and the hand element portion 34a when the mechanism is in the cocked position may be made such that the interconnection between the hammer pin 98 and the camming surface 99a will not lift the rebound lever end 31b completely out of engagement with the hand element portion 34a but, rather, will cause the two to have bare contact relationship when the desired position has been achieved. In this connection, it will be noted that the pin 98 will engage a different location along the camming surface 99a when the mechanism is in its double-action cocked position as shown in FIGURE 4 from that at which it will engage when the mechanism is in its single-action cocked position as shown in FIGUREQ. Accordingly, the camming surface 99a can be shaped to effect such bare contact engagement between the rebound lever end 3112 and the hand element portion 3411 at either cocked position. Alternatively, the bias pressure of the spring element (or 93) may be adjusted to afford this desired condition of operation.

However, such careful arrangement of the camming surface 99a, or such careful adjustment of the tension of the spring 90 (or 93) for the purpose of adapting the mechanism so as to have virtually zero trigger pull may be avoided by inclusion of the adjustable trigger pull mechanism as described in my referred to Patent No. 3,245,167. Thus, the invention in its preferred embodiment includes a spring-biased plunger mounted for slidable movement within a bore 146 of the trigger 27. The bore 146 extends upwardly through the trigger 27 at a location such that, at the firing position of the trigger (FIGURES 2 and 4), the upper end of the bore faces a horizontal portion 148 of the frame 21. The plunger 150 has a reduced diameter tip portion 152 which extends out through a correspondingly reduced diameter portion of the trigger bore 146 at its upper end, as indicated on the drawings. The reduced diameter of the plunger and trigger bore serve to permit the tip of the plunger to protrude out toward the horizontal portion 148 of the frame while preventing the plunger itself from coming out of the bore. A coil type trigger spring 154 extends within the bore 146 and urges the plunger 150 upwardly towards the horizontal portion 148 of the frame 21. The amount of outward force exerted by the spring 154 is controlled by means of an adjustment setscrew 156 which threadedly engages the lower end of the bore 146. There may also be provided an additional locking setscrew 158 to maintain a given setting of the adjustment setscrew 156.

As illustrated in FIGURE 2, when the trigger 27 has moved to its retracted position whereat its single-action sear 81 is in interlocking engagement with the singleaction sear 52 of the hammer 29, the plunger 150 is in slightly depressed condition against the horizontal portion 148 of the frame 21. It will be seen that when the trigger is in this position the trigger 27 encounters resistance to further rearward movement because the plunger 150 now extends between the spring 154 and the frame element 148, the plunger being out of engagement with the narrowed upper end of the trigger bore 146. The amount of resistance is equal to the bias pressure of the spring 154, and it will be understood that such effectuates return spring pressure on the trigger 27 which will serve the purpose of holding the interlock between the trigger sear 81 and the hammer sear 52 when the mechanism is in its single action cocked position as shown in FIGURE 2.

The same resistance or pressure tending to return the trigger 27 towards its released position as is effected by the plunger 150 also obtains when the trigger has achieved its triggering or firing position during the double-action movement of the mechanism as shown in FIGURE 4.

It becomes apparent that, where the trigger pull adjustment means 150, 154 is included, the positioning and curvature of the rebound lever camming surface 99a need not be so accurate as to maintain the interlock relation between the hammer and trigger sear elements while fully relieving the return spring pressure of the rebound lever 31 on the trigger 27 at the terminal portion of the cocking movement. Rather, the camming surface 99a and hammer pin 98 may be arranged to lift the rebound lever end 3117 completely out of engagement with the hand element portion 3411 so long as the tension in the trigger spring 154 is adjusted such that the plunger 150 commensurately exerts some minimal pressure upon the frame element 148. Moreover, the amount of tension in the spring 154 may be accurately reduced, by downwardly threading movement of its adjustment screw 156, to an extremely small value, or increased to a value whereby a substantial force must be exerted on the trigger to overcome its bias and thus trigger the mechanism from its cocked position.

Further, with respect to the double action movement, it will be noted that inclusion of both the adjustable pull trigger means 150, 154 and the hammer pin and rebound lever cam arrangement 98, 99a, will cause operation such that the pull exerted by the finger on the trigger will become less and less as the trigger approaches its cocked or triggering position, especially where the additional rebound lever spring 90 (or 93) is also included. Such action results in greater shooting accuracy since the hand, exerting less pressure at the critical time of firing, will be more steady.

What is claimed is:

1. In a cartridge firing device, a firing action mechanism comprising a trigger mounted for movement to a position thereof triggering the mechanism to fire a cartridge, bias means urging said trigger against its said movement, and means independent of said trigger for engaging said bias means and relieving said urging of the latter on said trigger during at least the terminal portion of said trigger movement.

2. A firing action mechanism according to claim 1, wherein said bias means comprises a lever mounted for pivotal movement and spring means normally urging said lever toward said trigger, and said means for relieving said urging of the bias means comprises second spring means acting on said lever and exerting bias pressure in direction opposite to that of the first said spring means.

3. A firing action mechanism according to claim 1, wherein said bias means comprises a lever mounted for pivotal movement and spring means normally urging said lever toward said trigger, and said means for relieving said urging of the bias means comprises camming means including means mounted for movement responsive to said movement of the trigger and engaging said lever at least during the terminal portion of said trigger movement.

4. A firing action mechanism according to claim 3, wherein said camming means further includes a camming surface on said lever, said means mounted for movement responsive to said movement of the trigger being disposed for engagement with said camming surface at least during the terminal portion of said trigger movement.

5. A firing action mechanism according to claim 4, wherein said means for relieving said urging of the bias means further comprises second spring means acting on said lever and exerting bias pressure in direction opposite to that of the first said spring means.

6. A cartridge firing device comprising a hammer mounted for movement between a released position adjacent the cartridge to be fired and a cocked position, a trigger mounted for movement between a released position and a triggering position engaging said hammer, said hammer and trigger being disposed with respect to each other for substantially concurrent movement towards their said. respective cocked and triggering positions, movable bias pressure means normally urging said trigger towards its said released position, and means on said hammer for engaging said bias pressure means to move the same to relieve its said urging on the trigger at least during the terminal portion of said concurrent movement of the hammer and the trigger.

7. A cartridge firing device according to claim 6, wherein said hammer and trigger are each mounted for pivotal movement, said bias pressure means comprises a lever mounted for pivotal movement in direction toward and away from said trigger, and said means on the hammer comprises pin means positioned thereon a distance away from the axis of said pivotal movement of the hammer and for engaging said lever.

8. A cartridge firing device according to claim 7, wherein said hammer and said trigger are each movable to their respective cocked and triggering positions responsive to said movement of the other, and said lever has cam surface means for engagement by said pin means during at least the terminal portion of any such movement of said hammer and said trigger.

9. In a cartridge firing device having a frame, a firing action mechanism comprising a trigger mounted for movement to a position thereof triggering the mechanism to fire a cartridge, spring biased plunger means mounted on said trigger for engaging said frame during the terminal portion of said trigger movement, said plunger means normally exerting its bias pressure in direction toward said frame and being depressible against its said bias upon its said engagement with said frame, bias means mounted on said frame and urging said trigger against its said movement, and means independent of said trigger for relieving said urging of said frame mounted bias means during said period of engagement of said plunger means with said frame.

10. In a revolver type pistol having a frame, a barrel element, and a cartridge cylinder mounted for rotatable movement to a'position thereof aligning a contained cartridge with the barrel element: a firing action mechanism comprising a hammer mounted for movement between a released position adjacent said cylinder and a cocked position away from said cylinder, a trigger mounted for movement between a released position and a triggering position, said hammer and trigger each having sear means for engagement with the sear means of the other to provide substantially concurrent movement of said hammer and said trigger towards their said respective cocked and triggering positions, a hand element mounted on said trigger for movement in engagement with said cartridge cylinder to move the latter to its said position concurrently with said movement of the trigger to its said triggering position, mainspring means biasing said hammer towards its said released position, a lever mounted for movement on said frame and being normally biased .by said mainspring means into engagement With said hand element whereby said trigger is normally biased towards its said released position, means independent of said trigger for substantially completely relieving said engagement of the lever with said hand element during a terminal portion of said trigger movement to its said triggering position, and spring bias means depressible during said terminal portion of, and in response to said trigger movement to its said triggering position to urge said trigger towards its said released position whereby said engagement between said hammer and trigger sear means is retained during said terminal portion of said trigger movement to its said triggering position.

11. A firing action mechanism according to claim 10, wherein said hammer and trigger sear means are adapted with respect to each other to provide a short distance of cocking movement of the hammer whereby the mechanism is characterized as providing a short through hammer during said cocking movement of the same, and said means for relieving said engagement of said lever with said hand element comprises second spring means urging said lever against the bias of said mainspring means whereby the tension of said mainspring means is increased.

12. A firing action mechanism according to claim 11, wherein the bias tension of said second spring means is adjustable.

13. A firing action mechanism according to claim 11, wherein said hammer and said trigger and said lever are each mounted for pivotal movement on said frame, said means for relieving said engagement of said lever with said hand element further comprises pin means attached to said hammer in spaced relation with respect to the axis of said pivotal movement of the latter and camsurface means on said lever for engagement by said pin means, said hand element being mounted on said trigger for rectilinear movement relative to said trigger, and said trigger having means for inducing said rectilinear movement of the hand element responsive to said movement of the trigger to its said triggering position.

14. A firing action mechanism according to claim 10, wherein said means for relieving said engagement of said lever with said hand element comprises lever camming means interconnecting said hammer and said lever.

15. A firing action mechanism according to claim 14, wherein said hammer and said trigger and said lever are each mounted for pivotal movement on said frame, and said lever camming means comprises a pin attached to said hammer at a location spaced from the axis of said pivotal movement of the latter, and means on said lever providing a camming surface thereof for engagement by said pin.

16. A firing action mechanism according to claim 15, wherein said means on said lever comprises means providing a notch extending inwardly from an edge of the lever.

17. In combination, a hammer adapted for pivotal mounting in a cartridge firing device and having a laterally projecting pin attached thereto at a location spaced from its axis of pivotal movement, and a lever adapted at one of its ends for pivotal mounting in said device in lateral adjacent relation with respect to said hammer and generally below the axis of pivotal movement of said hammer when the latter is so mounted, said lever having means defining an elongated notch extending inwardly thereof from its upper edge at a location therealong for engagement by said hammer pin during said pivotal movement of the hammer.

'18. A hammer and a lever according to claim 17, wherein said lever notch is arcuately curved whereby said engagement thereof by said hammer pin induces pivotal movement of said lever in direction toward the axis of pivotal movement of said hammer.

References Cited UNITED STATES PATENTS 698,440 4/1902 Brown 4269 BENJAMIN A. BORCHELT, Primary Examiner. 

10. IN A REVOLVER TYPE PISTOL HAVING A FRAME A BARREL ELEMENT, AND A CARTRIDGE CYLINDER MOUNTED FOR ROTATABLE MOVEMENT TO A POSITION THEREOF ALIGNING A CONTAINED CARTRIDGE WITH THE BARREL ELEMENT: A FIRING ACTION MECHANISM COMPRISING A HAMMER MOUNTED FOR MOVEMENT BETWEEN A RELEASED POSITION ADJACENT SAID CYLINDER AND A COCKED POSITION AWAY FROM SAID CYLINDER, A TRIGGER MOUNTED FOR MOVEMENT BETWEEN A RELEASED POSITION AND A TRIGGERING POSITION, SAID HAMMER AND TRIGGER EACH HAVING SEAR MEANS FOR ENGAGEMENT WITH THE SEAR MEANS OF THE OTHER TO PROVIDE SUBSTANTIALLY CONCURRENT MOVEMENT OF SAID HAMMER AND SAID TRIGGER TOWARDS THEIR SAID RESPECTIVE COCKED AND TRIGGERING POSITIONS, A HAND ELEMENT MOUNTED ON SAID TRIGGER FOR MOVEMENT IN ENGAGEMENT WITH SAID TRIGGERING CYLINDER TO MOVE THE LATTER TO ITS SAID POSITION CONCURRENTLY WITH SAID MOVEMENT OF THE TRIGGER TO ITS SAID TRIGGERING POSITION, MAINSPRING MEANS BIASING SAID HAMMER TOWARDS ITS SAID RELEASED POSITION, A LEVER MOUNTED FOR MOVEMENT ON SAID FRAME AND BEING NORMALLY BIASED BY SAID MAINSPRING MEANS INTO ENGAGEMENT WITH SAID HAND ELEMENT WHEREBY SAID TRIGGER IS NORMALLY BIASED TOWARDS ITS SAID RELEASED POSITION, MEANS INDEPENDENT OF SAID TRIGGER FOR SUBSTANTIALLY COMPLETELY RELIEVING SAID ENGAGEMENT OF THE LEVER WITH SAID HAND ELEMENT DURING A TERMINAL PORTION OF SAID TRIGGER MOVEMENT TO ITS SAID TRIGGERING POSITION, AND SPRING BIAS MEANS DEPRESSIBLE DURING SAID TERMINAL PORITON OF, AND IN RESPONSE TO SAID TRIGGER MOVEMENT TO ITS SAID TRIGGERING POSITION TO URGE SAID TRIGGER TOWARDS ITS SAID RELEASED POSITION WHEREBY SAID ENGAGEMENT BETWEEN SAID HAMMER AND TRIGGER SEAR MEANS IS RETAINED DURING SAID TERMINAL PORTION OF SAID TRIGGER MOVEMENT TO ITS SAID TRIGGERING POSITION. 